Winning MOC-off entry for:
General Magma -VS- Space Gypsy !!!
I have added some extra builds, including some in the background. I also made some stuff for the backstory.
I have also made a biography with information about this bounty hunter, by the name of X'rivzarr B'ro'dugar.

X'rivzarr B'ro'dugar was a mysterious bounty hunter, whose species and origins remained unknown. He was never seen without his armor, and remained quiet most of the time.
However, sometimes he talked, with a deep, dark and mysterious voice.

He had fought during many battles alongside the Sith, and stood victorious many times.
His armor was made from a very strong type of metal, and deflected most blaster bolts.

It was not capable of blocking lightsabers, but it did provide some protection against lightsaber slashes, however. His weapon was a modified minigun. The original model's use dated back to the time of Darth Malak. X'rivzarr modified the minigun with a more powerful energy source, and two metal plates to deflect blaster bolts and for protection against other things. He always wore a brown-colored cape, which he retrieved from the first Jedi he had ever killed.

After one of the leaders of the Bounty Hunter Guild had seen his skills and amazing actions during a battle on Nal Hutta, the Bounty Hunter Guild of Nar Shaddaa had invited X'rivzarr to become a part of the guild. X'rivzarr accepted the offer, however, there was one more thing he had to do.

The Bounty Hunter Guild designed a special wardroid prototype.
All of the prototypes were stolen by the Galactic Republic, to prevent the bounty hunters to cause damage to them. They were reprogrammed to fight for the Republic.

X'rivzarr received his first task he had to complete for the Bounty Hunter Guild: disable, and destroy if he had to, the prototypes, and return the intact droids back to the guild.

He travelled to the planet of Trandosha, as most of them were recorded to be present on that planet. He travelled on further, towards the grasslands, and found the wardroids there. Only two of the droids remained intact, and thus were brought back to the guild. They were reprogrammed for the second time, to serve under the guild once more.
X'rivzarr was from then on officially a member of the guild. Following that,
Slack the Hutt allowed X'rivzarr to join his subclan: Slack the Hutt's Mercenary Clan.

The bounty hunter also fought during the Battle of Taris, which took place during the Cold War. The battle started in some parts of the destroyed city, that was bombarded by the Sith Fleet 300 years earlier. Darth Magma and Darth Kluc'zor were at the frontline, where the first pair of Jedi was killed. Later, the bounty hunters who fought alongside the Sith Empire, including X'rivzarr, also arrived. X'rivzarr was able to end the lives of three Jedi Knights during that battle.

Most of the remains of the buildings around them collapsed as a Republic Hammerhead-class cruiser crashed into the surface of the planet.
The surviving Jedi and Republic troopers managed to escape to another part of the planet,
with the Sith Empire's participants following them.

(This part of the backstory is for this MOC)
With the increasing number of Jedi and neutral smugglers who attacked the Sith Empire,
X'rivzarr collected some more trash and metal dumped inside a building, to construct his best help for that battle: his multi-laser cannon, which was mounted onto his back.

Smugglers reached the building and started attacking X'rivzarr, but he fought back.
His multi-laser cannon was capable of firing three blaster bolts at once, making it very powerful for use against multiple enemies. As a smuggler prepared to attack him from behind, X'rivzarr turned around, and a fight broke loose inside the building.

The Battle of Taris from during the Cold War were the latest and thus most recent recordings of X'rivzarr's backstory, for now.

Well, here's the main MOC I made as an extra build for X'rivzarr, and my MOC-off entry.
Here you can see X'rivzarr in action, aswell. Enjoy the rest!

X'rivzarr fires a laser bolt into a smuggler's chest with his multi-laser cannon,
and destroys a recon droid with his minigun.

Recon droid blowing up.

This unfortunate smuggler is shot in the chest, and will be dying soon..

The fire and damage, caused by X'rivzarr.

Overview of the front part of the MOC.

If you look at the background here, you can see Taris city
being attacked by Sith starfighters. I made it as part as a background for this MOC.

Dead smuggler.

Another view of the background I made. Some more pictures of it:

Sith Empire's starfighters are attacking the buildings of Taris city.
Also, note the microscale minifigure down on the surface, trying to escape.
We all know that he will utterly fail.

This is the control panel X'rivzarr used to open the door, right before
the smuggler attacked him.

A micro version of a small (Sith) Imperial hovertank, entering the city.

Here's the city being attacked, again.

Tower of one of the buildings. Note the round window in micro-scale.

X'rivzarr B'ro'dugar, who's finished killing the threats.

X'rivzarr B'ro'dugar - Minifigure Details

X'rivzarr, with his trusty minigun.

Side view of X'rivzarr.

Back view of X'rivzarr. Here you can see the multi-laser cannon, mounted onto his back.
The axe piece is actually a piece of armor, used to protect the laser cannons and blasters, to prevent them from being destroyed easily.

The amount of blaster bolts X'rivzarr can fire at a time,
including the use of his minigun.

X'rivzarr without his minigun equipped.

Bonus picture: X'rivzarr B'ro'dugar, obtaining his cape from the first Jedi he had ever killed. This picture shows the cape in a good condition, before becoming battle-damaged.

_______________________________________________________________________________________Read this too:

That was my MOC-off entry, which won. The category was "purist bounty hunter minifigure".
The extra builds, biography and backstory are for more and extra points, given by the judges. Hope you enjoyed reading through his biography and backstory!